The worst part of losing Rose was the memory of all the things they hadn't shared. In the few short months they'd been lovers before Torchwood had stolen her from him, he'd managed to cross off many dreamed-of kisses, but there were still hundreds on his list.
They'd raced home one day, hand-in-hand, and he'd pressed her to the door and snogged her until her laughter turned to moans and she was no longer just breathless from the run. But he'd never twirled her around the console and kissed her as he dipped her low in the blue-green light of the time rotor.
They'd shared sleepy morning snogs in the galley when he handed her her first cuppa of the day, but he'd never surprised her by climbing into the shower with her and trailing kisses down her neck until she leaned back against his chest.
He'd taken her back to Woman Wept and kissed her beneath the frozen waves, after whispered confessions from both that they'd wanted this the first time they'd gone there. But they'd never made it back to New Earth so he could spread out his coat and make love to Rose surrounded by the sweet smell of apple grass.
There'd been a time when the fear of losing Rose had kept the Doctor from her. Even if she'd been able to spend her forever with him, he still would have lost her one day. For a while, he'd been convinced that the happy memories of his sixty or seventy years with Rose would make the centuries without her unbearable.
But now he knew better. Losing himself in the memories of their time together was his only source of happiness. If anything was unbearable, it was the memory of kisses not taken.